Urothelial papilloma

Urothelial papilloma is a rare benign lesion of the urothelium.

General

• Rare.
• Males > females (1.9:1).

Notes:

• If the person has a history of a low grade papillary urothelial carcinoma... it is likely a low grade papillary urothelial carcinoma.
• These cases are a consensus diagnosis, i.e. you show it to a colleague... if they agree you can call it.

Gross

• Exophytic lesion.

Microscopic

Features:

• Papillary fronds.
• Minimal branching or fusion.
• Cytological features of normal urothelium.
  • Normal urothelium approx. 2x the size of stromal lymphocytes.
• No mitoses.
• Thickness < 7 cells.^{[citation needed]}

DDx:

• Low grade papillary urothelial carcinoma.
• PUNLMP.

See also

• Urothelium.
• PUNLMP.
• Inverted urothelial papilloma.